Vasotab, a vasoactive peptide from horse fly Hybomitra bimaculata (Diptera, Tabanidae) salivary glands.

Journal article

Horse flies feed from superficial haematomas and probably rely heavily on the pharmacological properties of their saliva to find blood. Here we describe the first evidence of vasodilators in horse fly Hybomitra bimaculata (Diptera, Tabanidae) salivary gland extract and clone and express one of the active peptides (termed vasotab). Physiological tests using crude salivary gland extracts and reverse-phase HPLC fractions demonstrated positive inotropism in isolated rat hearts, vasodilatation of coronary and peripheral vessels, and Na, K-ATPase inhibition. One of the vasoactive fractions was analysed by N-terminal Edman degradation and a 47-amino-acid sequence obtained. A full-length cDNA encoding the peptide was cloned from a phage library using degenerate primer PCR and the peptide expressed in insect cells. A 20-amino-acid signal sequence precedes the mature 56-amino-acid vasotab peptide, which is a member of the Kazal-type protease inhibitor family. The peptide has a unique 7-amino-acid insertion between the third and fourth cysteine residues. The recombinant peptide prolonged the action potential and caused positive inotropism of isolated rat heart myocytes, and may be an ion channel modulator.

Authors: Takác, P; Nunn, M; Mészáros, J; Pechánová, O; Vrbjar, N

• Publication status: Published
• Journal: Journal of experimental biology
• Volume: 209
• Issue: Pt 2
• Pages: 343-352
• Publication date: 2006-01-01
• DOI: 10.1242/jeb.02003
• EISSN: 1477-9145
• ISSN: 0022-0949
• Language: English
• Keywords: Amino Acid Sequence; Heart; Complex Mixtures; Organophosphorus Compounds; Sequence Analysis, DNA; Base Sequence; Rats; Diptera; Salivary Glands; Animals; Chromatography, High Pressure Liquid; DNA Primers; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Vasodilator Agents; Sodium-Potassium-Exchanging ATPase; Sarcolemma; Molecular Sequence Data; Peptide Hormones